The present invention generally relates to automated guided vehicle systems, and in particular relates to a system for automatically uncoupling trolleys.
Automatic guided vehicles (AGV) are widely used in a variety of industrial environments, including factories and hospitals. They move automatically from one location to another, generally following a guide wire or track. They are intended to efficiently transport materials from location to location without requiring a vehicle driver.
AGV""s generally pull carriers, referred to as trolleys, on which goods to be transported are placed. Trolleys are attached to the AGV, usually at the back, by couplings. When an AGV arrives at a preprogrammed destination, an operator is responsible for decoupling any trolleys that have reached their destination.
Generally, AGV""s are programmed to stop at particular destinations for short periods of time. In most instances, an AGV is programmed to stop for about 1 to 4 minutes. Short waiting periods increase transport system efficiency. However, if an operator fails to meet the AGV while the AGV is stopped and waiting, the AGV continues on to the next destination with the trolley still attached. When this happens, the AGV needs to be rerouted (reprogrammed) through the facility, which diminishes the AGV system""s productivity and worker efficiency. There is an unsatisfied need for more efficient AGV systems.
The present invention provides systems and methods that reduce the number of mis-routed trolleys in an AGV system. The invention provides a solenoid driven automatic coupling for coupling a trolley to an AGV. When an AGV arrives at a particular preprogrammed destination, as determined for example by track patches read by the AGV, the AGV system switches the solenoid power causing the automatic coupling to free the trolley to disengage from the AGV. The AGV may then pull away from the trolley, leaving the trolley at its programmed destination. The system substantially eliminates the risk of a trolley not being uncoupled prior to the AGV""s departing from the trolley""s intended destination.
One aspect of the invention provides a coupling system adapted to couple an automatic guided vehicle to a trolley including an engagement member and a keeper, the engagement member moveable between an engaging position for engaging the keeper in an interference fit and a disengaging position for releasing the keeper from the interference fit, an actuator, which may be the same structure as the engagement member, moveable between a locking position and an unlocking position, a solenoid acting against the actuator according to a control current, and a controller for switching the control current, wherein switching the control current causes the actuator to move from the locking to the unlocking position, in the locking position, the engagement member is restricted from moving from the engaging position to the disengaging position, and in the unlocking position, the engagement member is either in the disengaging position or is free to move to the disengaging position.
Another aspect of the invention provides an automatic guided vehicle including a body and a coupling including a solenoid, the coupling being attached to the body and adapted to engage the automatic guided vehicle with a trolley, wherein switching a control current to the solenoid permits a trolley engaged by the coupling to the automatic guided vehicle to be disengaged from the automatic guided vehicle.
A further aspect of the invention provides a method for automatically disengaging a trolley from an automatic guided vehicle including providing an automatic guided vehicle with a coupling and a system for automatically disengaging the coupling and configuring the system to disengage the trolley according to a programmed location.
A further aspect of the invention provides an automatic guided vehicle including means for coupling the automatic guided vehicle to a trolley and means for automatically disengaging the trolley from the automatic guided vehicle.
A further aspect of the invention provides an automatic guided vehicle system including a plurality of automatic guided vehicles, a plurality of trolleys, and automatically operable couplings for engaging the automatic guided vehicles to the trolleys, wherein the automatically operable couplings release the trolleys according to location of the automatic guided vehicles.
The invention extends to features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative examples of the invention. These examples are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.